@article{oai:repository.dl.itc.u-tokyo.ac.jp:00025506,
 author = {有沢, 浩},
 journal = {東京大学農学部演習林報告},
 month = {},
 pages = {21--37},
 title = {クマゲラの営巣密度及び営巣木},
 volume = {84},
 year = {1991}
}